Initial lag when updating velocity values in FixedUpdate

Unity Engine
1 
FixedUpdate() {
    rigidBody2D.velocity = transform.up * speed * amplification;
}

I have an object that starts out going really fast and then gradually goes slower until is reaches X speed. Currently I have it so that I tween the “amplification” value from 30 to 1 over 1 second, then the object proceeds to move at its normal velocity.

Using this method, upon app startup on android, the first time this object appears (2 at a time), the frame rate plummets from 30 to ~15 for about a second. Then all subsequent objects, even after a scene reset, don’t affect the frame rate at all until the app is restarted.

So my question is, why the initial lag, but afterwards it’s fine? And is there a better way to code this initial burst of speed while still having rigidbody2D velocity control the object’s normal speed?

2

Bump

3

  1. Can you provide the full code for this class? At least the relevant parts.

  2. did you try waiting a few seconds before creating the first speeding objects? Perhaps the slow down is caused by something else entirely.

  3. what unity version are you on.